Golf club head

ABSTRACT

A hollow golf club head having a face portion, a sole portion, a side portion, a crown portion, and a hosel portion is configured such that a principal portion of the crown portion is made of a fiber-reinforced plastic (FRP body), and the remaining portions are made of a metal (metal body). An opening is disposed in the face portion, and a face plate made of an amorphous metal is fitted therein, and fixedly attached thereto by means of caulking. The remaining portions of the metal body are made of a crystalline metal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hollow golf club head, and particularly to a golf club head having a shape of a wood type or a shape approximating the same.

2. Description of the Related Art

A metal golf club head of a hollow structure has come into wide use as a wood-type golf club head, such as a driver or a fairway wood. Generally, a hollow wood-type golf club head has a face portion for hitting a ball; a crown portion forming the upper surface of the golf club head; a sole portion forming the lower surface of the golf club head; a side portion forming side faces on its toe, rear, and heel sides; and a hosel portion. A shaft is inserted into the hosel portion, and fixed by means of an adhesive, or the like. Recently, a number of golf clubs called utility clubs are commercially available. A variety of golf clubs having heads analogous to the above-mentioned wood-type golf club head (that is, having a face portion, a sole portion, a side portion, a crown portion and a hosel portion) are also commercially available as a type of such utility golf clubs.

As a metal forming the hollow golf club head, an aluminum alloy, stainless steel, or a titanium alloy has been used. Among them, a titanium alloy in particular has been in wide use in recent years.

When a hollow golf club head is increased in volume, the sweet spot thereof can be expanded. In order to prevent the increase in volume from leading to an increase in the weight of the golf club head, consideration has been given to employing as the constituent material of the golf club head a fiber-reinforced plastic whose specific gravity is lower than those of the above-listed metals. In this case, since the surface of the face for hitting a ball must be made of a metal in order to ensure strength, portions other than the face are made of a fiber-reinforced plastic.

JP-A-2004-16654 discloses a golf club head wherein a face portion, a front portion of a golf club head continuous with the face portion, and a center portion in a width direction of a sole portion are made of metals, and the remaining portions are made of a CFRP.

SUMMARY OF THE INVENTION

JP-A-2004-16654 includes no description about use of an amorphous metal as the metal.

The present invention aims at increasing coefficient of restitution of the metal face portion of a golf club head whose crown portion is made of a fiber-reinforced plastic, thereby providing a golf club head which can increase a carry distance of a golf ball.

According to an embodiment of the invention, there is provided a hollow golf club head having a face portion, a sole portion, a side portion, a crown portion and a hosel portion, wherein a principal portion of the crown portion is made of a fiber-reinforced plastic; at least the face portion and a front edge portion of the crown portion continuous with the face portion are made of a metal; and the portion of the crown portion made of the fiber-reinforced plastic is affixed to a rear end surface and an inner surface of the front edge portion, which is made of a metal, of the crown portion.

Preferably, all portions made of a metal are made of an amorphous metal.

Preferably, a peripheral edge portion of the face portion is made of a crystalline metal, and a face plate made of an amorphous metal is fixedly attached to the peripheral edge portion.

Preferably, a front edge portion of the side portion and a front edge portion of the sole portion are made of a metal continuous with the face portion; a center portion of the sole portion in a toe-sole direction is made of a metal continuous from the metal front edge portion of the sole portion; and the metal portion at the center of the sole portion extends to a rear portion of the golf club head.

Preferably, all portions other than the principal portion of the crown portion are made of a metal; portions other than the face portion are made of a crystalline metal; a peripheral edge portion of the face portion is made of a crystalline metal; and a face plate made of an amorphous metal is fixedly attached to the peripheral edge portion.

Preferably, the face plate made of an amorphous metal is fixedly attached to the peripheral edge portion of the face made of a crystalline metal, by means of caulking the peripheral edge portion side of the face.

The golf club head according to the embodiment of the present invention is configured such that the main portion of the crown portion is made of a fiber-reinforced plastic. Accordingly, the crown portion is easily deformed upon hitting of a ball, thereby exhibiting a favorable restitution property. In addition, the golf club head can be reduced in weight.

In the configuration of the invention, at least the center portion of the face portion is made of an amorphous metal. Since the amorphous metal is higher in strength and lower in elasticity than a crystalline metal, when the face portion is reduced in thickness so as to increase the degree of deformation thereof upon hitting of a ball, restitution is increased, whereby a carry distance of a golf ball can be increased.

Meanwhile, unlike a crystalline metal, an amorphous metal is difficult to process by means of forging, presswork, or welding. To this end, when all the portions made of a metal are made of an amorphous metal and integrally welded, manufacturing can be facilitated. In addition, the following configuration may also be alternatively employed. Namely, a peripheral edge portion of the face portion is made of a crystalline metal, portions other than the peripheral edge portion of the face portion are formed into a face plate made of an amorphous metal, and the face plate is fixedly attached to the peripheral edge portion by means of caulking, or the like.

BRIEF DESCRIPTION OF THE DRAWING

These and other objects and advantages of this invention will become more fully apparent from the following detailed description taken with the accompanying drawings in which:

FIG. 1 is a perspective view of a golf club head according to an embodiment of the invention;

FIG. 2 is a perspective view of a metal body of the golf club head of FIG. 1, as viewed from the front;

FIG. 3 is a perspective view of the metal body of the golf club head of FIG. 1, as viewed from the rear;

FIG. 4 is a side view of the metal body of the golf club head of FIG. 1, as viewed from the heel side;

FIG. 5 is a plan view of the metal body of the golf club head of FIG. 1;

FIG. 6A is a longitudinal cross-sectional view of the golf club head of FIG. 1, taken along a line in the front-rear direction, and FIG. 6B is an enlarged view of a portion of FIG. 6A;

FIGS. 7A and 7B are longitudinal cross-sectional views of a rear portion of a golf club head according to another embodiment of the invention, wherein FIG. 7A shows the state before attachment of a plug-like member, and FIG. 7B shows the state after attachment of the same;

FIG. 8 is a exploded perspective view of a metal body for use in another embodiment;

FIGS. 9A and 9B are cross-sectional views showing an attachment structure of a face plate of the metal body of FIG. 8;

FIG. 10 is a exploded perspective view of a metal body for use in yet another embodiment; and

FIG. 11 is a cross-sectional view of a golf club head provided with the metal body of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the invention will be described by reference to the drawings. FIG. 1 is a perspective view of a golf club head according to the embodiment of the invention. FIG. 2 is a perspective view of a metal body of the golf club head, as viewed from the front. FIG. 3 is a perspective view of the metal body, as viewed from the rear. FIG. 4 is a side view of the metal body, as viewed from the heel side thereof. FIG. 5 is a plan view of the metal body. FIG. 6A is a longitudinal cross-sectional view of the golf club head taken along a line in the front-rear direction. FIG. 6B is an enlarged view of a portion of FIG. 6A.

A golf club head 1 is a wood-type hollow golf club head having a face portion 2, a sole portion 3, a side portion 4, a crown portion 5, and a hosel portion 6. The golf club head 1 is configured with a metal body 10 wholly made of an amorphous metal, and a fiber-reinforced plastic body (hereinafter referred to as “FRP body”) 20.

As an alloy composition constituting the amorphous metal, a zirconium amorphous alloy is preferable, and a zirconium amorphous alloy represented by a general formula ZrMX is particularly preferable, where M is one or more metal elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Ti, Mo, W, Ca, Li, Mg, Si, Al, Pd and Be, and X is one or more metal elements selected from Y, La, Ce, Sm, Md, Hf, Nb and Ta. Meanwhile, the amorphous metal may be a completely amorphous metal, or a semi-amorphous metal which partially includes crystalline metal.

The metal body 10 includes the face portion 2, a metal sole portion 13, a metal side portion (toe) 14, a metal crown portion 15, a metal side portion (heel) 16, a metal back portion 17, an annular portion 18 disposed in the metal back portion 17, and the hosel portion 6.

The face portion 2 is a face for hitting a ball, and unillustrated grooves (score lines) are disposed thereon. The sole portion 3 forms the lower surface of the golf club head. The side portion 4 forms the side faces on the toe, heel, and rear-face sides. The crown portion 5 forms the upper surface of the golf club head. A shaft is inserted into the hosel portion 6 and fixedly attached thereto by means of an adhesive.

The metal body 10 forms the face portion 2, the front edge portion of the crown portion 5, the front edge portion of the side portion 4, the front edge portion of the sole portion 3, the center portion of the same in the lateral direction (in the heel-toe direction), and the rear face portion of the golf club head.

The metal crown portion 15 forming the front edge portion of the crown portion 5 is continuous with the metal side portion (toe) 14 and with the metal side portion (heel) 16. The metal side portion (toe) 14 and the metal side portion (heel) 16 are respectively continuous with the metal sole portion 13. The metal side portions 14, 16 and the metal sole portion 13 are continuous with the face portion 2.

The front portion of the metal sole portion 13 extends across the golf club head from the toe side to the heel side thereof. The metal sole 13 is gradually decreased in width rearward from the front portion. The rear portion of the metal sole portion 13 is disposed at the center portion of the golf club head in the heel-toe direction. The metal back portion 17 is continuous with the rear end of the metal sole portion 13. The metal back portion 17 rises obliquely backward from the metal sole portion 13. The annular portion 18 is formed integrally with the inner surface of the metal back portion 17. An opening is provided through the annular portion 18 and the metal back portion 17. A female thread (not shown) is provided on the inner peripheral face of the opening.

The amorphous metal body 10 can be manufactured by means of casting a molten alloy into a die, followed by cooling at a designated cooling rate or faster. The cooling rate is determined in consideration of the amorphous metal composition.

The FRP body 20 forms the remaining portions of the external surface of the golf club head 1. More specifically, the FRP body 20 forms a rear half portion of the crown portion 5, a rear half portion (excluding the metal back portion) of the side portion 4, and portions of the sole portion 3 other than the metal sole portion 13.

The FRP body 20 is shown in enlarged view in FIG. 6, and is in close contact with the end surfaces of the metal crown portion 15, the metal side portions (both toe and heel) 14 and 16, and the metal sole portion 13. The FRP body 20 is also in close contact with the inner surfaces of the edges of the same in an overlapping manner. Particularly, in the metal crown portion 15, the FRP body 20 reaches the back surface of the face portion 2 as shown in FIG. 6B. More specifically, the FRP body 20 is in close contact with the entire inner surface of the metal crown portion 15 in an overlapping manner.

In order to form the FRP body 20 and integrally join the same with the metal body 10, the metal body 10, whose inner surface has been subjected to primer treatment as required, is placed in a die whose inner shape is identical with an outer shape of the golf club head. Subsequently, laminated prepreg sheets (an uncured resin-fiber composite material sheet) are disposed along the inner surface of the die and the inner surface of the edge of the metal body 10. Meanwhile, the laminate may be pre-formed in advance so as to fit along the inner surface of the die. Thereafter, the resin is heated in a state where gas pressure is applied to the inside of the die through the opening of the annular portion 18, to thereby be cured. In relation to the above, the following method may alternatively be adopted. That is, a resin bag of nylon or the like is disposed inside the golf club head in advance. Gas is supplied into the bag to thus inflate the bag, thereby pressing the prepreg sheet so as to bring the prepreg sheet into close contact with the inner surface of the die.

Accordingly, the FRP body 20 is formed; and simultaneously, the peripheral edge portion 21 of the FRP body 20 is brought into close contact with the end surface and the edge portion of the metal body 10, as shown in FIG. 6. After completion of the molding, the golf club head is released from the die, and a vibration absorption layer and/or a ball-hitting sound adjustment layer is formed on the inner surface of the golf club head as required. For instance, by means of forming into the shape of a layer a pressure-sensitive adhesive composed of polyisobutylene, or the like, the golf club head can be prevented from generating an empty sound.

A plug-like member 30 (not shown in FIGS. 1 to 6) is screwed into the opening of the metal back portion 17. The female thread for this screwing may be provided in the metal body 10 in advance or after release from the die. Thereafter, the external surface of the golf club head is subjected to grinding and painting as required, thereby obtaining a golf club head product.

The plug-like member is preferably made of a material having a high specific gravity, such as tungsten, so as to bring the center of the gravity of the golf club head to a deeper position.

Meanwhile, the plug-like member 30 may be fixedly attached into an opening 40 of the annular portion 18 by means of brazing, adherence, interference fit, or the like, as shown in FIG. 7. The plug-like member 30 has a columnar portion 31, and a flange portion 32 provided at the rear end of the columnar portion 31. The opening 40 of the annular portion 18 has a step portion 41 in an entrance portion of the opening 40. The flange portion 32 is engaged with the step portion 41.

As the plug-like member 30, a tungsten-nickel-iron (W—Ni—Fe) alloy having a high specific gravity of about 10 to 12 can be used. A suitable composition of the alloy is as follows:

-   -   W: 28 to 32 wt %;     -   Fe: 45 to 49 wt %;     -   Ni: 15 to 17 wt %; and     -   Cu: 1 to 2 wt %.

An alloy of the above composition can be subjected to casting. The alloy of the composition is rich in Fe, and superior in weldability with metals containing components such as stainless steel and iron. Therefore, the alloy can be welded easily even by TIG welding, a general welding method.

The club head configured as above, the metal body 10 including the face portion 2 thereof is made of an amorphous metal. Accordingly, when the face portion 2 is reduced in thickness so as to increase the degree of deformation thereof upon hitting of a ball, restitution is increased, whereby a carry distance of a golf ball can be increased. Meanwhile, thickness of the face portion 2 (excluding the peripheral edge portion) is suitably about 1 to 4 mm, particularly suitably about 1.5 to 3 mm. The peripheral edge portion of the face portion 2 may be thicker than this. Since a rear half of the golf club head is mainly made of the FRP body, the golf club head is lightweight and can be increased in size.

In addition, the FRP body 20 is affixed also to the inner surface of the edge of the metal body 10 in an overlapping manner. Accordingly, bonding between the metal body 10 and the FRP 20 is firm, and exhibits excellent durability. Meanwhile, the average value of the width of the metal crown portion 15 and those of the metal side portions 14, 16 in the front-rear direction (i.e., the face-back direction) is preferably about 2 to 20 mm, particularly preferably about 5 to 18 mm.

The golf club head according to the embodiment, the metal sole portion 13, the metal side portions 14, 16, and the metal crown portion 15 are disposed all around the circumference of the face portion 2. Accordingly, the peripheral edge portion of the face portion 2 has high rigidity. Therefore, even when the face portion 2 is reduced in thickness, the metal body 10 as a whole is provided with a required strength.

In the golf club head, the front edge portion of the sole portion 3 is formed from the metal sole portion 13. Accordingly, even when the front edge portion of the sole portion 3 hits the ground (in a so-called “sclaffing”) during the course of a swing, the front edge portion of the sole portion 13 is not damaged.

In the golf club head, the metal sole portion 13 extends in the front-rear direction at the center of the sole portion 3. Accordingly, the center of gravity of the golf club head can be lowered, whereby a ball can be hit high. In addition, since the metal sole portion 13 extends rearward, the center of gravity of the golf club head is brought to a deeper position, thereby expanding the sweet spot. In addition, the annular portion 18 is disposed in the metal back portion 17, which is continuous with the metal sole portion 13 at the rearmost end thereof, and the plug-like member made of a high specific gravity material is fixedly attached to the annular portion 18. Accordingly, the center of gravity is brought to a further deeper position.

In the embodiment, a portion of the hosel portion 6 is disposed inside the golf club head as shown in FIG. 3. Accordingly, the center of gravity can be lowered.

In addition, when the portion of the hosel portion 6 is disposed inside the golf club head as described above, torsional moment applied to the shaft at the time of hitting a ball is reduced, whereby side-to-side runout of the thus-hit ball is suppressed. Meanwhile, by means of reducing the protrusion length of the hosel 6 out of the external surface of the golf club head, the external appearance of the golf club head also becomes favorable.

The length of the portion of the hosel portion 6 protruding into the golf club head is desirably 10 to 50 mm, particularly desirably 20 to 50 mm, and further particularly desirably 35 to 45 mm.

In the embodiment, the entire metal body 10 is made of an amorphous metal; however, a metal body configured as follows may also be employed. That is, portions of the face portion other than the peripheral edge portion are made of an amorphous metal; and portions of the metal body other than the face portion, and the peripheral edge portion of the face portion are made of a crystalline metal. A metal body 50 shown in FIGS. 8 to 9, and a metal body 70 shown in FIGS. 10 and 11 are respectively configured as follows.

Similar to the metal body 10 shown in FIGS. 1 to 7, the metal body 50 shown in FIGS. 8 to 9 includes a face portion 52, a metal sole portion 53, a metal side portion (toe) 54, a metal crown portion 55, a metal side portion (heel), a metal back portion 57, an annular portion 58, and a hosel portion 56.

The metal crown portion 55 forming the front edge portion of the crown portion is continuous with the metal side portion (toe) 54 and with the metal side portion (heel). The metal side portion (toe) 54 and the metal side portion (heel) are respectively continuous with the metal sole portion 53. The metal side portion 54 and the metal sole portion 53 are continuous with the face portion 52.

The front portion of the metal sole portion 53 extends in the overall width of the golf club head from the toe side to the heel side thereof. The metal sole portion 53 is gradually decreased in width from the front portion rearward. The rear portion of the metal sole portion 53 is disposed at the center portion of the golf club head in the heel-toe direction. The metal back portion 57 is continuous with the rear end of the metal sole portion 53. The metal back portion 57 rises obliquely rearward from the metal sole portion 53.

The annular portion 58 is formed integrally with the inner surface of the metal sole portion 53. An opening is provided to penetrate the annular portion 58, and a female thread (not shown) is provided in the inner circumferential surface of the opening. The plug-like member 30 (not shown in FIGS. 8 to 9) is screwed into the annular portion 58.

In the metal body 50, portions referred to above are made of a crystalline metal. Examples of the crystalline metal include lightweight metals such as titanium, a titanium alloy, and an aluminum alloy.

In the metal body 50, an opening 60 is disposed so as to leave the peripheral edge portion of the face portion 52. A face plate 52 f made of an amorphous metal is fitted in the opening 60, and fixedly attached thereto. In the embodiment, a step portion 61 is disposed on the inner peripheral edge portion of the opening 60; and on the front face of an element assembly of the metal body 50 before attachment of the face plate 52 f, a flange portion 62 is provided along a circumference of an edge portion of the opening 60. A recessed step portion 63 is provided circumferentially along the peripheral edge portion on the front-face side of the face plate 52 f in a surrounding manner. The face plate 52 f is fitted to the opening 60 so as to contact the step portion 61. Thereafter, the flange portion 62 is caulked to thus crimp the recessed step portion 63. Consequently, the face plate 52 f is fixedly attached to the peripheral edge portion of the face portion 52.

As a result of being substantially tabular, the face plate 52 f can be manufactured easily even when made of an amorphous metal. As a result of being made of a crystalline metal, the metal body other than the face plate 52 f can be manufactured easily by means of any of a variety of methods, such as casting, forging, press, cutting, and welding.

The metal body 50 shown in FIGS. 8 to 9 is configured by means of disposing the opening 60 in the face the metal body 10 shown in FIGS. 1 to 7, and attaching the face plate 52 f to the opening 60. A golf club head including the metal body 50 is analogous to the golf club head shown in FIGS. 1 to 7, except that the metal body 10 is replaced with the metal body 50.

FIG. 10 is a perspective view of the metal body 70 wherein the side portion and the back portion of a golf club head are also made of a metal, and a face plate 72 f made of an amorphous metal is fixedly attached to the face portion. FIG. 11 is a cross-sectional view taken along a front-rear longitudinal line of a golf club head including the metal body 70.

The metal body 70 includes a face portion 72, a sole portion 73, a side portion (both toe and heel) 74, a metal crown portion 75, a back portion 77, and a hosel portion 76.

The metal crown portion 75 forms only the peripheral edge portion of the crown portion of the golf club head. The remaining portions of the crown portion other than the peripheral edge portion form an opening 79, into which an FRP body 90 is fitted.

In the face portion 72 of the metal body 70, an opening 80 is disposed so as to leave the peripheral edge portion of the face portion 72; and the face plate 72 f made of an amorphous metal is fixedly attached in the opening 80. The metal body 70, not including the faceplate 72 f, is made of an crystalline metal. Suitable examples of the crystalline metal include lightweight metals such as titanium, a titanium alloy, and an aluminum alloy. The opening 80, which has a configuration analogous to that of the opening 60 of the metal body 50, is brought into contact with a step portion 81, and the edge portion of the opening 80 is caulked. Accordingly, the face plate 72 f is fixedly attached to so as to seal the opening 80.

The FRP body 90 is fixedly attached to the metal body 70 in the same manner as in the FRP body 20 shown in FIGS. 1 to 7. In the embodiment, the FRP body 90 is fixedly attached to the upper surface of the metal crown portion 75 in an overlapping manner. Although not illustrated, the metal body 70 may also be provided with a plug-like member made of a high specific gravity material.

A golf club head including the metal body 50 shown in FIGS. 8 to 9, or a golf club head including the metal body 70 shown in FIGS. 10 and 11 is also provided with the metal face plate 52 f, 72 f, which is made of an amorphous metal in the face portion. Accordingly, when the face portion is reduced in thickness so as to increase the degree of deformation thereof upon hitting of a ball, restitution is increased, whereby a carry distance of a golf ball can be increased.

In the invention, by means of adjusting the orientation of reinforcement fibers in the crown portion of the FRP body, rigidity in the front-rear direction (face-back direction) may be rendered lower than that in the toe-heel direction (lateral direction). When such an adjustment is effected, deformation of the crown portion upon hitting a ball is increased, thereby increasing a launch angle of a ball. As a result, a carry distance (flight distance) of the hit ball increases.

As prepreg for forming the FRP body, either cross fiber prepreg or unidirectional fiber prepreg may be used.

The prepreg is preferably used in the form of laminated prepreg with 3 to 8 sheets.

As the fiber in the prepreg, carbon fiber or the like whose elastic modulus is about 20×10³ to 30×10³ kg/mm² is suitable; however, the fiber is not limited thereto.

As described above, the elastic modulus of the crown portion in the front-rear direction is preferably rendered lower than that in the toe-heel direction by means of adjusting the orientation of the fibers. For instance, cross fiber prepreg and unidirectional fiber prepreg are laminated alternately, and the fiber orientation of the unidirectional fiber prepreg is caused to align in a direction parallel to the toe-heel direction.

As a resin for the FRP body, a thermosetting resin such as an epoxy can be used. Meanwhile, a small amount of thermoplastic resin may be mixed into the thermosetting resin, thereby enabling an improvement in vibration-absorbing property.

The FRP body is preferably about 1 to 3 mm in thickness. In particular, the crown portion is preferably about 1 to 2 mm, particularly preferably about 1 to 1.5 mm; for instance, about 1.3 mm.

The invention is suitable in application to a large head of a volume greater than or equal to 300 cm³, particularly greater than or equal to 350 cm³; for instance, 350 to 400 cm³. Manufacture of a very large head having a volume of about 600 cm³ is technically feasible. The weight of the golf club head is suitably about 160 to 200 g, particularly suitably about 180 to 190 g.

The foregoing description of preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. 

1. A golf club head of a hollow shell structure comprising: a face portion; a sole portion; a side portion; a crown portion; and a hosel portion, wherein a principal portion of the crown portion is made of a fiber-reinforced plastic, at least the face portion and a front edge portion of the crown portion continuous with the face portion are made of a metal, and at least a center portion of the face portion is made of an amorphous metal.
 2. The golf club head according to claim 1, wherein all portions made of a metal are made of an amorphous metal.
 3. The golf club head according to claim 1, wherein a peripheral edge portion of the face portion is made of a crystalline metal, and a face plate made of an amorphous metal is fixedly attached to the peripheral edge portion.
 4. The golf club head according to claim 1, wherein a front edge portion of the side portion and a front edge portion of the sole portion are made of a metal continuous with the face portion, a center portion of the sole portion in a toe-heel direction is made of a metal continuous with the metal front edge portion of the sole portion, and the metal portion at the center of the sole extends to a rear portion of the golf club head.
 5. The golf club head according to claim 1, wherein all portions other than the principal portion of the crown portion are made of a metal, portions other than the face portion are made of a crystalline metal, and a peripheral edge portion of the face portion is made of a crystalline metal, and a face plate made of an amorphous metal is fixedly attached to the peripheral edge portion.
 6. The golf club head according to claim 3, wherein the face plate made of an amorphous metal is fixedly attached to the peripheral edge portion of the face portion made of a crystalline metal, by means of caulking the peripheral edge portion of the face portion.
 7. The golf club head according to claim 1, wherein a thickness of the face portion falls within a range of 1 to 4 mm.
 8. The golf club head according to claim 4, wherein an average value of a width of the metal front edge portion of the crown portion and those of the metal front edge portion of the side portion in a front-rear direction falls within a range of 2 to 20 mm.
 9. The golf club head according to claim 1, wherein rigidity of the crown portion made of the fiber-reinforced plastic in a front-rear direction is rendered lower than that in a toe-heel direction.
 10. The golf club head according to claim 1, wherein the fiber-reinforced plastic is made of carbon fiber whose elastic modulus falls within a range of 20×10³ to 30×10³ kg/mm².
 11. The golf club head according to claim 1, wherein a thickness of the crown portion made of the fiber-reinforced plastic falls within a range of 1 to 2 mm.
 12. The golf club head according to claim 1, wherein a volume of the golf club head falls within a range of 350 to 400 cm³, and a weight of the golf club head falls within a range of 160 to 200 g. 